Timer for internal-combustion engines



July 21, 1925.

BrvOLKMAR TIMER FOR INTERNAL COMBUSTION ENGINES Filed Dec. 9, 1920Inventor:

Patented July 21, 1925.

PATENT OFFICE.

BERNHARD VOLKMAR, OF NEW YORK, N. Y.

TIMER- i on INTERNAL-COMBUSTION ENGINES.

, Application filed December 9, 1920. Serial No. 429,315.

To all whom it may concern:

Be it known that I, BERNHARD VOLKMAR, a citizen of the United States,residing at the borough of Bronx, in the city of New York, county ofBronx, and State of New York, have invented certain new and usefulImprovements in Timers for Internal-Combustion Engines, of which thefollowing is a specification, reference being bad therein to theaccompanying drawings, which form a partthereof.

y invention relates to timers for internal combustion engines, and moreparticularly to a mechanism of this character having a particular formof contact brush adapted to be assembled and-used in connection with ashiftable commutator ring now commonly used in connection with theengines in a certain well known and popular lowpriced automobile.

In timing mechanisms of the character to which my invention relates, ithas been the general practice to employ a roller mounted upon aspring-pressed oscillatory bell crank lever, said roller being mountedupon a fixed pivot in said arm. In the above construction there are twopivots which, to ensure freedom in the movement of the brush support,must be oiled from time to time, and sufficient weight in the supportfor the brush to cause the lever to oscillate against the tension of itsspring, either from the-result of sudden jars to which parts about anautomobile engine are constantly subjected, or as a result of the impactof the roller with irregular surfaces of the commutator. In factcommutators employing brushes of the character above referred to. are soirregularly worn as to accentuate the conditions above referred to,Jumping of the brush with relation to the commutator quite frequentlycauses an engine cylinder to miss lire alto-a gether, or a delay in thefiring of the cylinder, thus interferring with the smooth running of theengine. I I

With the above conditions in mind, I have produced a timing devicewherein the brush will be maintained in constant, continuous engagementwith all sections of the commu'tator and wherein the working conditionswill be such that there will be no irregular wear in said commutator.

A brush made in accordance with my invention is so constructed as toensure accuracy in the closing of the circuit to the coils under allconditions and a continuity in the flow of the current for the entirelength of the contact se ments of the commutator. Furthermore, thecontact area between the brush and the commutator will be suflicientlygreat to ensure against sparking. The contact itself is so constructedas to avoid excessive wear-of parts, notwithstanding-the high speed ofrotation of the roller of the brush, and the device is free from pivotalsupports of all kinds which would require oiling to avoid undue wearthereon.

The invention consists in a timer for in ternal combustion enginesembodying therein the combination with a commutator ring, of a brushadapted to be rotated in synchro' nism with the engine shaft, consistingof a hub, a radially extending housing having parallel side walls, asubstantially cylindrical roller slidabl v and rotatably mounted insaidhousing with its sides in substantial engagement with the sidewallsthereof, a spring in said housing having a normal tendency to thrustsaid roller through and be yond the open end of said housing, and awear, plate between said spring and said roller, whereby scoring of thesurface of said roller is prevented, said spring being held undertension by the enagagement of said roller with said commutator ring; andin such other novel features of construction and combination of parts asare hereinafter set forth and described, and more particularly pointedout in the claims hereto appended.

Referring to the drawings,

Fig. 1 is an elevation of a commutator ring and a brush embodying myinvention associated therewith. on the line 11 of Fig. 3, a portion ofthe housing of the brush being broken away;

Fig. 2 is a detail vertical section through the brush; and

Fig. is a section on the line 3-3 of Fig. 1. Y

Like'letters refer to like parts throughout the several views.

In the embodiment of my invention shown in the drawings, a indicates anold and well known construct-ion of commutator housing carrying acommutator ring pro-- vided with the contact segments 1, 2, 3 and 4,each having associated therewith the usual binding post 1 2 3 and 4:.Said segments and said binding posts are insulated from each other andfrom the housing a by suitable insulating materialiiicluding a ringZiwhich is recessed to receive said contact segments. Said housing andits commutator are adapted to be oscillated by means of asiiitable leversystem connected with thelug c to advance or retard the spark. Thisgeneral construction and arrangement is old and well known in the artand no claim of invention is made thereto;

Associated with said commutator is brush mechanism which is rotated111;Sy1flchronism with the engine shaft, preferably by being mountedupon an extension thereof, which "is indicated at (Z in the drawings.Thisbrush comprises a hub 6 having a suitable slot therein adapted toco-operate with a pin 7 upon the shaft (Z soqas to facilitate themounting and removing of the brush with relation to the shaft to causeit to rotate therewith.

The hub e'is provided with a radially extended housing g, the open topof which terminates adjacent the commutator ring, sufficient clearancebeing aiforded to avoid possible contact of the end of the housing withsaid commutator. v The chamber of the housing 9' is rectangular insection to accommodate the sub stantially cylindrical contact roller hand permit the free rotary movement of said roller and a reciprocatorymovement there of radially of the hub c with the two-fold v object oflimiting the rotary movement of said roller to an axis parallel to thatof'said hub and permitting the roller to recede within the housing tofit the brush to the commutator ring and to compensate forirregularities iii the surface of said ring cooperating with theroll-er. 1 It isv to be observed that said roller /b has no arbors andno fixed axis of rotation, its axis of rotation being variable accordingto the variations from a true circle in the commutator ring, should suchexist or develop, f Within the housing 9 is ajcoiled spring 2' which isnormally'held under tension by the roller h as a result of its movemntia- V war-(11 of said housing, a wear plate being interposed betweensaid spring and the,p'e-- rin'ieter of said roller to avoid abrasion ofthe contact surface of said roller from the enact the tempered spring.

The spring 71 has suflicient strength to 7 The roller h possesses solittle weight in itself that it will have little tendency toinoveagainst the tension of said spring as a re suit of jars or jolts uponthe vehicle, the

tendency toward displacement of the roller inwardly of the housingagainst the tension of said spring by such olts and ars being furtherminimized by the action of centrifugal force.

The housing 9 for convenience of manua facture has been made of softmetal, and.

since wear thereon will occur uponthe rear wall of the chamber thereinas determined by the direction of rotation of thehousing, I provide saidwall with a wear plate 70 against which the said roller will be thrustas a result of the frictional engagement thereof withthe commutator ring3 To facilitate the assembling,handling'and mounting of the brush, theforward ant rear walls at the open end of the housing are. crimpedslightly after 7 the; roller is mounted therein, so that said rollerwill be held against displacement by the inturned metal of said wallsandthus pr vent displacement of the roller. Said crimped edges will notbe subject to wear or interfere with the free rotationof sa d roller,since the in= ward movement of the roller, to ensure its engagement withthe commutator ring, will prevent the engagement of the roller with saidcrimped portion while it is function a The operation of the hereinClGSU'lbBLl timing mechaiiism is suhstantiallyas follows lii assemblingthe brush in a timer, the casing a is removed andthe hub a mounted uponthe shaft d by means of the pin f, said housing and its commutator r ngbeing then 1. i

replaced, the roller 71 being depressed against the tension ofthe springz'so as to, bring this roller within and in engagement with theoperative surface of 's'aid ring. As the roller ,thus recedes withinsaid housing 9 the contact surface thereof will be engaged onl'v w ththe wear plate 7' until the shaft (Z is rotated, whence this surfacewill also contact with the wear plate 7:; at the rear all of the openingin 'said h'ousing. ,Since the sides of the roller have afree runningfitawith the parallel side walls of the opening in said housing, thereill be no 'stichfriction developed as will require any, lubricationotthe device, and thus the liabiiity of an on film being'fo'rmed upon 1,2, 3 or 4: to the pistons 7 as x its

the contacts 1, 2, 3 and 4 is eliminated. As stated above, when thebrush is assembled in the timer, the contact surface thereof does notengage the inturned forward and rear edges at the open end of thehousing.

iVhen the spring 2' is tensioned in the manner above described, it willforce the roller h outwardly with suflicient force to maintain it inconstant engagement with the commutato ring so as to ensure accuracy inthe timing of the ignition of the explosive charge in the respectiveengine cylinders, and maintain the circuit closed for a perioddetermined by the length of each con tact segment. I have found inactual practice that severe jarring of the vehicle will have no tendencyto cause the disengagement of said roller from the commutator ring, andthat a roughened surface of said ring will not interfere in any way withthe timely making and maintenance of a perfect contact. In fact I havefound, when using a brush made. in accordance with my invention, with abadly corrugated commutator ring, that there was notonly no loss of, norinterruption in, the contact, but that with a continued running of theengine, the ring will be brought to a true smooth surface.

The constant thrust of the spring 2' and the constant engagement of thewear plate 7' with the roller h as a result of such thrust, ensurescontinuity in the ground connection through the brush and the shaft (i,there being no possibility or likelihood of the partial or completeinsulation of these parts by reason of the presence of an oil filmthereon. Furthermore the constant wiping action of the roller with saidwear plate and with the wear plate k ensures bright, clean contact areasbetween the roller and the conducting medium for leading the current tosaid shaft d.

It is not my intention to limit the invention to the precise details ofconstruction shown in the accompanying drawings, it being apparent thatsuch may be varied without departing from the spirit and scope of theinvention.

I have found the use of a roller h of cylindrical form capable of havingrotary movement about the axis parallel with the axis of the shaft d tobe absolutely essential in order to secure the'desired contact area withthe commutator ring, and to avoid undue wear upon the ring.

A brush made in accordance with my invention is subject to very slightwear, and I have observed no material wear upon the commutator ring as aresult of the engage ment of the brush therewith. Any such slight wearas does occur will be readily com: pensated for by the advance of theroller by the spring 2'.

The reduced wear upon the co-acting parts resulting from continued useof a brush made in accordance with my invention, will prolong the lifeof a timing mechanism and permit the inexpensive repair thereof in theevent of ultimate excessive wear, since any loss of tension in thespring as would interfere with the desired continuous contact of theroller, which loss might result from a decrease in the diameter of theroller as-a result of wear, may be remedied by mounting a new brush uponthe shaft cl and thus avoid the necessity for replacing of the casing aand its commutator ring.

Practice has heretofore demonstrated that wearupon the timer, such as tointerfere with its proper operation, is evidenced upon the commutatorring and not upon the brush mechanism, thus requiring the replacement ofthe commutator. This conditon, however, is reversed in a timer embodyingmy invention, since repairs can be efiected by merely replacing a wornbrush with a new one. s I have found in actual practice that enginetroubles attributed to the carburetor have arisen by reason of theimproper functioning of the timer, and that by the substitution of abrush embodying my invention, the apparent carburetor trouble has beenentirely eliminated.

Having described the invention, what 1 claim as new and desire to haveprotected 'by Letters Patent, is

1. A timer for internal combustion engines embodying therein thecombination with a commutator ring, of a brush adapted to be rotated insynchronism withthe engine shaft, consisting of a hub, a radiallyextending housing having parallel side walls, a wear plate for the rearwall of the opening in said housing with regard to the direction ofrotation of the brush, a substantially cylindrical roller slidably androtatably mounted in said housing with its sides in substantialengagement with the side walls thereof, the perimeter of said rollerbeing adapted to engage said Wear plate as the brush is rotated, aspring in said housing having a normal tendency to thrust said rollerthrough and beyond the open end of said housing, and a wear platebetween said spring and said roller whereby scoring of the surface ofsaid roller is prevented, said spring being held under tension by theengagement of said roller with said commutator ring.

2. A timer for internal combustion engines embodying therein a brushconsisting of a hub adapted to be detachably mounted upon a shaft, aradially extending housing having parallel side walls, a wear plate forthe rear wall of the opening in said housing with regard to thedirection of rotation of the brush, a substantially cylindrical rollerslidably and rotatably mounted in said housing with its sides insubstantial engagement with the side walls thereof, and its axisparallel with the axis of said hub, a metallic spring in said housinghaving a normal tendency to thrust In witness whereof I have hereuntoaiflxed said roller throughand beyond the open end my signature, 'in thepresence 'of t sub 10 of said housing, and a Wear plate between scribingWitnesses, this 8th day of December,

said spring andsaid roller whereby scoring 1920.

of the surface ofsaid roller is prevented, V BERNHARD VOLKMAR. and saidroller is caused to move toward a Witnesses: 1 commutator ring Withwhich the brush is I F. T. WENTWOR H,

adapted to cooperate. FRIEDA KOEHLER.

